A 3-phase induction motor is applied with a 400 V, 50 Hz supply and the motor runs at 1470 rpm. The rotor current will have a frequency of
- A. 50 Hz
- B. 4 Hz
- C. 2 Hz
- D. 1 Hz
Answer: D. 1 Hz
Explanation: Rotor frequency fr = s × f. For slip s = 0.02 and supply frequency 50 Hz, fr = 0.02 × 50 = 1 Hz.